Bad teeth, gum disease tied to risk of cancer-causing infection

NEW YORK — Gum disease and other dental ailments boost the risk of becoming infected with oral human papillomavirus, a sexually transmitted virus that causes 40 to 80 percent of all throat cancers, according to the first study to find such a link.

Those who said they had poor oral health had a 56 percent higher rate of oral HPV infection than those who reported good to excellent oral health, researchers wrote in a study published Wednesday by Cancer Prevention Research, a journal of the American Association for Cancer Research.

Oral HPV infection is similar to genital HPV infection in that there are low and high-risk variations. Low-risk oral HPV can spur non-cancerous tumors or warts in the mouth and throat while high risk may lead to cancers of the mouth and throat, the researchers said. Today’s study is the first to show a link between poor oral health and oral HPV infection, said Christine Markham, the study author.

“This is just another really good reason to take good care of your teeth and your mouth,” said Markham, an associate professor of health promotion and behavioral science at the University of Texas Health Sciences Center in Houston, in an Aug. 19 telephone interview. “Our findings show that even when you control for known risk factors for oral HPV infections such as smoking and oral sex behaviors, poor oral health is an independent risk factor for oral HPV infection.”

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Markham said poor oral health such as sores in the mouth or throat or inflamed gums may act as a portal allowing the HPV entry into the body, while those with good oral health don’t have those portals so even exposure to HPV doesn’t trigger an infection.

More research is needed to better understand the connection between bad oral hygiene and HPV infection, she said.

Most people with HPV infections of the throat and mouth have no symptoms and only “a very small percentage” develop into cancer, according to the American Cancer Society. There is currently no U.S. approved test for oral HPV infection.

Merck & Co.’s vaccine Gardasil prevents cervical cancer caused by the sexually transmitted virus in girls and boys. GlaxoSmithKline also sells an HPV vaccine. Neither is approved to prevent oral cancers. The virus infects 4 of 5 sexually active people at some point in their lives and is known to cause cervical, vulvar, vaginal, penile and anal cancer.

About 10 percent of men are orally infected with HPV, compared with 3.6 percent of women, according to a 2012 study.

Wednesday’s study looked at 3,439 people ages 30 to 69 years old who participated in the National Health and Nutrition Examination Survey conducted by the U.S. Centers for Disease Control and Prevention. The survey asked them to rate their oral health, whether they had gum disease, if they used mouthwash in the past several days to treat dental issues and how many teeth they had lost.

The researchers found that men, smokers, those who used marijuana and those who had multiple oral sex partners had a higher chance of oral HPV infections. Poor oral health also was independently linked to oral HPV infection.

The study found that those who had gum disease had a 51 percent higher rate of oral HPV than those without gum disease and those who had dental issues had a 28 percent higher prevalence.

This year about 36,000 people will get cancers of the mouth and throat and about 6,850 will die from the disease, according to the American Cancer Society.